From ABC News:
One of Jupiter's two main cloud belts has completely disappeared, to the surprise of scientists who study the solar system's largest planet. "This is a big event," says planetary scientist Glenn Orton of NASA's Jet Propulsion Lab. "We're monitoring the situation closely and do not yet fully understand what's going on." The brown ring of clouds, known as the South Equatorial Belt (SEB), is twice as wide as Earth and more than twenty times as long. Orton thinks the belt may not have disappeared, but could instead be hidden behind other clouds. Scientists say the belt has faded out before. (NASA)